Universal Serial Bus (USB) Type-C connectors, which are expected to be used in mobile computers and smartphones, allow use in conformity with not only USB but also other protocols. Thus, a USB Type-C connector can be shared by a plurality of protocols. Protocols such as Mobile High-definition Link (MHL), DisplayPort and Thunderbolt are already usable in USB TYPE-C connectors as alternative modes (hereinafter “Altmode”). High-Definition Multimedia Interface (HDMI [registered trademark]), which is the de facto video interface standard, will probably also be defined as an Altmode and available in USE TYPE-C connectors.